Japanese Patent Application Publication No. 2004-23854 (JP2004-023854A) discloses a motor including a stator core 203, a pair of end brackets 205 and 207 attached to both end portions of the stator core 203, and a rotor 209 configured to rotate inside the stator core 203. Four projecting portions 251 to 254 and 271 to 274 are formed respectively at four corners of the pair of end brackets 205 and 207. The projecting portions are fitted with four respective outer corners 231 to 234 and 235 to 238 of both end portions of the stator core 203 (see FIG. 7).
Japanese Utility Model Application Publication No. 05-67188 (JPU05-067188A) discloses a motor including a stator core 303, a pair of end brackets 305 and 307 attached to both end portions of the stator core 303, and a rotor configured to rotate inside the stator core 303. Cylindrical projecting portions 350 and 370 are formed at the pair of end brackets 305 and 307, respectively. A part of the cylindrical projecting portions 350 and 370 is fitted with a part of magnetic pole portions 310 (pole teeth 311) formed in the stator core 303 (see FIG. 8).
If the end brackets do not contact the magnetic pole portions (pole teeth) in the stator core as in the motor according to JP2004-023854A, the stator core and the rotor can face each other over a large area, which allows the motor to produce relatively high torque. With such a fitting structure, however, the stator core and the end brackets are fitted with each other only at several locations, which limits the rigidity of the motor and tends to cause vibration and noise from the motor.
If the projecting portions of the end brackets are fitted inside the stator core as in the motor according to JPU 05-067188 A, the stator core and the end brackets can contact each other over a large surface, which makes it possible to increase the rigidity of the motor and to reduce vibration and noise. With such a fitting structure, however, the projecting portions of the end brackets contact the magnetic pole portions (pole teeth) in the stator core, which reduces an area over which the stator core and the rotor face each other and accordingly reduces torque of the motor.